Knowde Enhanced TDS
Identification & Functionality
- Ingredient Name
- Food Ingredients Functions
- Ingredients
- Guar Gum
- Food Additive Number
- E 412, INS 412
- Technologies
- Sources
Guar Gum is a hardy and drought-resistant plant which grows 1- 2 m. high with vertical stalks. The seed pods grow in clusters on the vertical stalks. The pods are about 15 cm. long and hold six to nine seeds about 2–3 mm. diameter. Roughly, 14–16% of the seed is the hull. 38–45% represent endosperm and 40–46% germ. This annual plant is an ancient one and is presently grown extensively in Pakistan and India for human and animal consumption. It is also grown in the semi-arid, southwestern United States. The growing season is about 20 to 25 weeks. It needs little surface water for growing, and the pods must be haravested in the fall, preferably after the first frost and definitely before the next rain. If not, some of the seeds wither, die, and turn black. If these colored seeds are not removed, the quality of the gum is very poor.
In commercial processing, a variety of methods are sued to efficiently separate the guar endosperm from the hull and germ. The hull can be loosened by soaking in water and then removed by multistage grinding and sifting or by charring the hull by flame treatment. The differential grinding is used to separate the germ from the endosperm, since there is a difference in hardness of each constituent. Attrition, hammer, or roller mills may be used. The separated endosperm, containing about 80% galactomannan, is finally ground to a fine particle size to be sold as Guar gum. This is a white to yellowish-white, nearly odorless powder.
Features & Benefits
- Food Ingredients Features
Applications & Uses
- Markets
- Applications
- Food & Nutrition Applications
- Qualities
- Stablizing
- Thickening
- Controlling
- Uses
- Food & Beverages
- Paper & Te xtile
- Mining & Derivatives
- Water Treatment
- Pharmaceutical
- Cosmetic
- Tobacco
- Petroleum
Technical Details & Test Data
- Properties
Physical
Guar gum is practically odorless and has a bland taste. Its color is off white to very light yellow tan. Mesh sizes are readily available from 100 to 250.
Solubility
Guar gum will disperse and swell almost completely in cold or hot water. It is insoluble in organic solvents.
Viscosity
The most important characteristic of Guar is its ability to be dispersed in water and hydrate or swell rapidly and almost completely in cold water to form viscous colloidal dispersions or sols. The viscosity attained is dependent on time, temperature, concentration, pH, rate of agitation, and particle size of the powdered gum used. The lower the temperate, the lower the rate at which viscosity increases, and the
lower the final viscosity, Above 80° Celsius the final viscosity is slightly reduced. The finer Guar powders swell more rapidly than coarse powdered gum.
Chemical Characteristics
Guar gum, like Locust Bean gum, is a polysaccharide consisting of a straight chain of D-mannopyranose units joined by b - (là) linkages with a a side-branching unite of a single D-galactopyranose unit joined to every other mannose unity by a- (là6) linkages. Locust Bean gum has a single galactose side-branch every fourth mannose unit. The
molecular weight o Guar is 220,000 + 10%. Ths greater side-branching of Guar accounts for its cold water hydration as well as its greater hydrogen-bonding activity. An average quality Guar gum contains about 80% galactomannan, 12% water, 5% protein, 2% acid insoluble residue or crude fiber, 0.7% fat, a trace of heavy metals, zero arsenic, and zero lead.pH
A 1% Guar sol has a pH between 5 and 7. The optimum hydration rate occurs between pH 75 and 9. It has a very slight buffering action and is very stable from pH 4 to 10.5. The preferred method to prepare a sol having a very low or very high pH is to prepare a sol at the gum's normal pH and then adjust to as low as pH 1 or slightly above pH 10.5
to give stable sols.
Compatibility
Guar gum, being a nonionic polymer, is compatible with most other hydrocolloids. It is a compatible with most chemically modified starches, modified celluloses, synthetic polymers, and water-soluble proteins. Guar is compatible with many salts over a wide range of electrolyte concentration. Some multivalent salts affect hydration and
viscosity, and even produce gels. Borate ion present in alkaline water inhibits the hydration. If Guar gum is hydrated, a cohesive structural gel may be formed by the borate ion at pH 7.5 to 10.5. This gel is reversible by reducing pH below 7 or by heating the gel. Polysaccharides, having numerous cis hydroxyl groups, can form these three dimensional gels with pentavalent boron. The guar borate gel may also be liquefied by
addition of glycerol or mannitol, both low-molecular weight polyols.
Preservatives
Bacterial attack, common to all plant hydrocolloids, may be controlled by a mixture of 0.15% methyl and 0.02% propyl parahydroxybenzoate.